A production method of 2-(5-ethyl-5-hydroxymethyl-1,3-dioxane-2-yl)-2-methylpropane-1-ol (DOG) which includes a step of acetalizing hydroxypivalaldehyde with trimethylolpropane in a solvent in the presence of an acid catalyst. After the acetalization, the reaction product liquid is neutralized and then heated to dissolve the deposited DOG crystals. Then, the reaction product liquid is cooled to recrystallize DOG. DOG produced in such manner has an adequately large particle size. Therefore, DOG is easy to handle and involves little danger of dust explosion.